1. Field
This relates to an air conditioner.
2. Background
Air conditioners make use of a refrigerant cycle including a compressor, a condenser, an expansion mechanism, and an evaporator to heat/cool an indoor space and/or purify air. Air conditioners are classified into single-type air conditioners in which a single indoor unit is connected to a single outdoor unit, and multi-type air conditioners in which multiple indoor units are connected to one or more outdoor units.
The one or more outdoor units may include a compressing unit, an outdoor heat exchanger, an outdoor expansion mechanism, and an excessive cooler. The compressing unit may include a plurality of compressors. The number of operating compressors may vary according to indoor loads. One compressor may operate under a small load, and a plurality of compressors may operate under a great load.
When one of the operating compressors is stopped, the inside of the stopped compressor remains at a relatively high pressure, and should be decreased before re-starting. That is, discharge and suction pressures of the stopped compressor should be relatively balanced, or the stopped compressor may fail to re-start. Stopping another of the operating compressors to balance the high and low pressures of all the compressors and decrease the inner pressure of the stopped compressor may degrade the effectiveness of the indoor cooling or heating operation cannot be performed. In addition, when the stopped compressors restart, a large amount of time is required to reach a certain level of cycle performance, and may cause a delay in achieving a desired operating level when re-starting all of the compressors.